I recently was introduced to Tim Whelan who owns a photography bookstore in Rockport, Maine. It's an incredible place and Tim is an enthusiastic and generous supporter of photography in all its forms.
His shop holds treasures both old and new. Many editions and hard to find and often signed and offered at extremely reasonable prices, frequently better than what you might pay online. He knows many of the photographers whose books he sells and always has an interesting story about them. Plus, he sells a few select original prints (mostly black and white) that are absolutely stunning. For anyone living in the Northeast especially, it's almost worth the trip just for the store. (And maybe a lobster.
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I don't think he has a web site, but google Tim Whelan Photo books and you're sure to get some hits. If you were ever looking for a hard to find or out of print volume, he'd be a great resource.